Whether in the form of network scanning tools, bot-net infectors, viruses or worms, attacks against computer systems represent a significant threat which must be considered and countered by any business which uses this type of technology. Unfortunately, prior art methods for dealing with these attacks have several undesirable features. For example, many of these methods (e.g., anti-virus scanners) are purely passive, seeking to detect and block attacks against a system. While detecting and blocking attacks is valuable, it does not interfere with the operation of an attacker, or prevent the attacker from targeting other, potentially more vulnerable, machines on a network. Accordingly, there is a need in the art for an improved computer system defense tool which addresses one or more of the deficiencies found in the prior art.